engine off i have good brake pedal, engine on it goes to floor and i hear air when i push pedal. if i disconnect vacuum line from brake boost with engine on i get pedal, advise?

When you disconnect the booster vacuum you should get a very hard pedal. This could be an internal leak of the booster but you are going to want to pinpoint the air rushing noise. Use a cheap stethoscope to find the vacuum leak. Alex